As an aid when checking damages on crashed cars and on repairing these respectively it is known to use rulers constituted by an extendable, for instance telescopic part that is fixable to its length and in its ends are provided with measuring points. The ruler may be used for measuring or adjusted according to measures taken from an undamaged side or alternatively from a data sheet or drawing for the vehicle for comparisons. To this end the ruler is provided with scales. Since most mass produced vehicles are provided with a number of holes in the bottom of the body that are very precisely defined to their position one can with the aid of such a ruler comparatively simply through measuring between selected holes obtain a good measuring accuracy for cross measuring.
A drawback with these rulers is however that they are comparatively cumbersome requiring in particular at larger damages when the ruler becomes comparatively long and consequently difficult to handle and to locate with the required exactness with its points. In reality this often means that its a two person job with the resulting costs.
It is also known to arrange measuring systems on correction, or straightening benches that are used when repairing cars. These measuring systems and correction benches or fixtures are however very expensive and can only be acquired by firms with a sufficiently large volume of work and each bench can only take one car at a time. This means that many who actually would have to use measuring equipment can not afford it, but instead have to work instinctively.
Yet another time when a simple measuring is desirable is when a car has been damaged. A good knowledge of how badly damaged the car is, is necessary in order to enable the insurance company, the owner or the man who is to repair it if the car is worth repairing or if it should be broken up and to assess expected repair time and cost. Even here a simple measuring method with accompanying means would be desirable, provided that sufficient exactness can be achieved. To achieve the desired precision three-dimensional measuring is further desirable.
In view of the above problems the invention has as its object to provide a low-cost simply manageable measuring system for the measuring of the bottom plates of cars.
The system in accordance with the invention constitute in its most simple variety an extendable ruler or bar that in one end is provided with a measuring point and in the other end with a fastening means including a powerful magnet for the fixing to the underside of the vehicle and a centering device for the centering of the fastening means in relation to a measuring hole in the body. Since today very powerful magnets are available the end of the ruler may be firmly and securely be held to the body even if rust and/or underseal should be present around the hole.
When the ruler is fixed in one end the user may measure distances, compare left and right measures or compare with data sheets. The ruler is mounted in the magnetic fastening bracket and is preferably swivable laterally as well as vertically. In this way it can easily be moved to different measuring points or out of the ay without having to be dismounted. The ruler may easily be used by one person and even on cars that stand on their own wheels. The ruler can be extended to approximately the right distance, inserted under the car and with a simple movement be fastened to the car with the magnet and then the measurements can be controlled in the other end of the ruler or compared with a new reading with the magnet fastened to a symmetric location on the other side.
The centering device for the fastening bracket can be constituted of a cone pretensioned outwards by a spring. At mounting the cone is inserted into the hole and the fastening means is pressed against the hole until the magnet grips. Practically it has turned out that this fastening means result in a good grip that is also always centered in the hole. This also means that the fastening means is adaptable to different hole sizes and the invented fastening means can be used on a very great variety of cars without change of adaptors. With an easy bending movement the fastening means can be removed again. With the right relation between the cone angle, the spring force and the magnetic force, the spring of the cone can center the fastening means during the movement towards the mounted position or actually even after mounting since the force necessary to achieve lateral movement always is smaller than the holding force (since the friction coefficient is always smaller than 1). Even if this balance is not achieved it is easy to feel when the cone has reached its correct position, since the bracket will have a considerably increased resistance against movement away from this position.
The magnetic fastening means in the end of the ruler may be permanently fastened to this or preferably removably. Also for the connection to the ruler magnetic force can be used or a simple snap lock with a spring loaded ball and a circular groove.
The fastening means can according to the invention not only be used together with a ruler but may also be used to mount and center other measuring equipment increasing speed and precision when using these. For instance the rod in the small end of the ruler may in its upper end also be provided with a magnetic self-centering fastening means so that a specific length measure can be monitored while for instance straightening work is carried out.
In accordance with the system according to the invention the ruler may instead of being used together with the magnetic fastening bracket be used together with a transverse preferably self-centering beam that is fastened to the vehicle. By fastening the ruler to a central point on the beam measurements to different points on the right and left side can quickly be taken showing in figures how skewed or deformed the bottom is. The ruler may also be fastenable to points on the transverse beam situation on equal distance from the center to provide additional triangular measurements to provide the coordinates of measuring points.
A further part of the invented system is a device that delivers a line of light and that can be mounted either on the self-centering beam (preferably centered) or on a magnetic fastening bracket. When mounted on the self-centering beam the line automatically will provide a plane that is essentially horizontal or at least perpendicular to the vertical symmetry plane of the car. This means that it can be used as a reference for vertical measurements at least at symmetrical points, for instance by means of an adjustable measuring rod arranged in the outer end of the ruler and provided with a scale. To obtain exact measurements the rod has to be vertical but in order to compare the left and right side it is only necessary to compare readings without adjustments of the rod in the ruler, which in turn means very rapid comparing.
Instead of mound the light (laser) device giving the line on the transverse beam it can be mounted on a magnetic fastening bracket and adjusted so that it is perpendicular to the vertical symmetry plane.
In a more sophisticated development of the invented system using for instance the transverse beam the angles of the ruler laterally and vertically are electronically registered as well as the length of the ruler. In this way a connected computer may provide quickly and precisely a measuring chart of the vehicle, that can be compared with a corresponding data chart of what the measurements should have been. Also this version can to a certain extent be used with the car standing on its wheels. Connection to the computer may be wireless. This version of the invention has the advantage of requiring very little or perhaps no adjustment or precision on mounting since the computer from three undamaged points can relate the measuring to the actual datum plane of the vehicle.
It deserves to be mentioned that the invented system and its components allow not only simple and fast measuring, but it is also easy to understand how it should be used and no lengthy training or tutoring is necessary.